Sulfite liquor derivatives and processes



March 26, 1957 c. uscHMANN l 2,786,820

SULFITE LIQUOR DERIVATIVES AND PROCESSES rFiled Feb. 18, 1952 ATTORNEYS SULFITE. LIQUOR VDERIVATIVES AND PROCESSES Curt Uschinann, Lebanon, Greg., assigner to Cascades Plywood Corporation, Portland, Greg., a corporation of Delaware Application February 18, 1952, Serial No. 272,159

20 Claims. (Cl. 2GB-17.2)

This invention relates to a derivative of waste liquor of the sulte pulp manufacturing process. Such derivative may be utilized in various applications and may be modified in different ways, as most suitable for such applications. This application is a continuation-impart of my application Serial No. 779,465 resulting 'in United tates Patent No. 2,585,977 for Sulfite Liquor Treating Process and Product.

The derivative in itself or in modified form is useful as a varnish base, as a moldable plastic, as a hardening medium for synthetic rubber products, as la synthetic substitute for natural rubber and as a thermosetting binder for various purposes, either alone or in conjunction with other commercially available adhesives, and is particularly valuable for mixing with metallic pigments to afford colors resistant to fading and which can be used as an ingredient of a phenol-formaldehyde resin binder and pigment mix to render the phenol-formaldehyde yresin and pigment compatible, andthereby prevent appreciable fading.

Either by itself or mixed with other binders the sulte liquor derivative may be utilized advantageously in fabrieating wood products, such as wallboard, synthetic lumber, and a variety of pressed or molded articles `using woody material tibersprocured fromwood zwaste, bagasse, corn stalks, etc., or for .bonding veneer sheets `in the manufacture of plywood andin veneering furniture.

it is a lparticular object of my process to employ a treatment procedure which, while being effective to convert the ,useful ingredients of the sultite waste liquor into binder material, can-be carried out economically by utilizing simple equipment, by adding to the liquor in the recovery process only small ,amounts of inexpensive materials, and by accomplishing the relining treatment in a short period of time.

Depending upon the particular purpose for which the resultant lbinder fis to be used, the process may be varied to alter the proportions or types of ingredients ,added to the sulte liquor during the recovery process, or blended with the resultant product of such process after its completion.

Details of my preferred process are described more particularly hereafter, and in the drawings representative apparatus suitable for use in the performance of such process is illustrated.

The ligure of the drawings is a top perspective view of apparatus which may be used in conjunction with my process, elements of it being shown rather kdiagrammatically and parts ybeing'brolten away4 to disclose features of its construction. i

The process of reclaiming waste sulfte liquor and treating it to produce a Vderivative of the type to vwhich this invention pertains consists generally o f heating the sulte liquor, preferably to the boiling point, and Vat Vintervals during such heating process adding reactive ingredients toit. The rrst ,step ,duringsuehheatingpropesa following its concentration .to greater or lesser extent, if deied States Patent O "ice Patented Mar. 26, 1957 sired, is to alkalize the liquor with a caustic alkali, such as sodium or potassium hydroxide.

.In the example of the suitable process to which my Patent 2,585,977 lmentioned above relates, after the alkalized liquor has been treated for a length of time sucient to render it uniform the aldehyde furfural is added to the liquor. Again the heating is continued for a time suiieient to insure the substantial `completion of -the reaction between components of the liquor and the added aldehyde. For certain purposes Vvthe product obtained from the treatment ,of the waste ,suliite liquor to this point may be utilized as a binder, such, for example, as in the manufacture of low density fibrous products from woody bers impregnated with such binder.

lf desired, the process may be continued, and while the liquor is still hot, phenol can be added to yit. The resulting product has excellent water-proof and -binding qualities, suitable eitherfor-use in making ber products, such as hardboard `or synthetic lumber, -by admixture with fibrous woody material, or as `an adhesive for veneer :in the manufacture of plywood or furniture.

ribis product can `also be used as the base for a `synthetic material capable of use as a substitute for natural rubber, as will be explained in .greater detail hereinafter.

in an alternative process the phenol and furfural tare added simultaneously yto vthe alkalzed sulte liquor, and may have beenmixed together before thus being added, or the phenol -is added to the alkalized sulflte liquor first and subsequentlythe furfural is added. `When the furfural yis added to the alkalized sultite liquor simultaneously with the phenol or subsequently to its addition to the alkalized vsultite liquonno ebullition occurs. Moreover, theproduct resulting when `the mixture of alkalized liquor, phenol and furfural in this instance-is-heated for a timeis not alheavy or `viscous liquid, asis the product of the alkalized suliite liquor and furfural Vreaction discussed above, -or the product where, after such reaction, phenol is added in a subsequent step. Gn the contrary, thebulk ofthe mixture `increases and .for-ms a colloid of thin gelatinous consistency instead of being a viscous resinous liquid.

When to the colloid product'of `this alternate procedure a ketone, such as `acetonernethylethylltetone, methyl-isopropyl ketone, methyl-butyl ketone, methyliso-butyl ketone, or methylsbenzyl ketone, is added, however, the

water phase of the mixture is separated Vfromlthe viscous portion so that a viscous resinous liquid comparable to that obtained from the iirstprocessdescribed settles and the water rises.

It is possibleto-treat waste sulte liquor in the manner described generally above in a batch process, but this is comparatively slow, because after treatment of one batch has been completed, the heating of the new batch must be started and the various steps 4described-must'be performed'sequentially before affurther batch can be treated. Preferably theprocess steps are carried out simultaneously on various portions of Lliquor passing step-by-step through apparatus, such as from one container to the next, one step of the process being Vperformed in each container.

The apparatus shown in the drawing includes a lstorage reservoir 1 'for wastesu'liitefliquor from which it may be drained through a-pipe 16 continuously at a rate which may be determined by adjustment of the valve '11 Vinthat pipe. The liquid in iowing out of the pipe preferably is discharged from a header 12 perforated along its lower side, which extends along one edge `of a heated concen trating device or vaporizerZ. i

The concentrating `device includes a shallow pan 20 inclined from its edge beneath header pipe `12 gently downwardly to its `discharge opening 121. Preferably the discharge opening extends entirely across the rlower edge ofthe pan, or .nearly soandfthersize -ofiits iopen' ing .may `be Yregulated `by suitable means (not shown) 4if practically colorless to aV light brownish tint.

chamber -22 of. the vaporizer 2 beneath the pan` 20. The

hotuid may be supplied to such chamber through a Ypipe 23 and exhausted through a pipe 24, so that the hotter lluid will pass beneath that portion of the pan adjacent tothe discharge opening 21, although the direction of circulation is optional. The fluid may be released into the heating chamber, or circulated through it confined in heating coils, as may be preferred.

Because the header 12 distributes the sultite liquor over substantially the entire width of the vaporizer pan 20,

Ait will ow in a thin sheet downwardly to the discharge K opening 21 at a velocity determined by the angle at which the pan is tilted. Preferably-passage ovcr'the pan will require n otA less Vthan l0 minutes, and should be at least suiticient to raise the temperature of the liquor tov its boiling point. Y During this passage preferably a substantial portion of the Water will be evaporated from the sultite liquor, the amount depending upon the temperatureof the sheet, the velocity of the liquid over it, 'and the quantity of flow regulated by the adjustment of valve 11, although such concentration of the liquor is not essential. The resulting steam and fumes, such as sulfur dioxide and of terpenes vaporized, will be collected by the hood 25 covering the pan 20, and will be conducted by pipes 26 out of the pan to remove objectionablev vapor.

The more or less concentrated liquor flowing out of the pan through the discharge opening 21 is deposited in one end of a tank 3 which has a plurality of parallel partitions 30, alternate partitions projecting from oppov side sides of the tank across the major portion of its width to form a serpentine trough for flow of the liquor from its inflow end adjacent to vaporizer 2 to a discharge opening 31 at its opposite end. During the passage of the liquor through this trough, its heating is continued by circulating hot lluid, such as steam, through a` compart- Vment 32 beneath the tank 3. Such uid may be supplied to this chamber through a pipe 34 and discharged from itthrough a pipe 35. Again such iiuid may be released directly into the chamber, or circulated through heating coils. Preferably this tank is substantially horizontal so that the liquor will ll the serpentine trough to a considerable depth controlled by the height of the weir at the entrance to the outlet 31.

To the liquor in tanki3 caustic valkali is added in controlled amount, preferably being supplied near the inflow end of its serpentine trough. The caustic may be stored in a container 36 from which it is fed through pipe 37 into the tank in an amount controlled by regulation of valve 38. From such tank the hot alkalized liquor is poured into a vat 4 through the discharge spout 31. This vat is heated by hot iiuid, such as steam, supplied through a pipe 40 to the space 41 between inner and outer walls of the vat, from which jacket space the iiuid is discharged lthrough pipe 42. While in this vat, the liquor not only is heated, but is stirred continuously by the paddles 43 of an agitator, which are carried by a rotary shaft 44.

In accordance with the process described in my aforesaid Patent No. 2,585,977, to the liquor heated in vat 4 is added the aldehyde. Conveniently this can be stored in a supply tank 47 and dispensed at will through pipe 48, in quantities controlled by valve 49 in such pipe, into the trough 31' to mix with the liquor as it llows into the vat. The contents preferably are heated to boiling temperature, substantially that of water, and the agitation is .v continued until the interaction ofthe aldehyde and liquor components is complete, the time required being between ve and thirty minutes. Ebullition occurs during the reaction between the alkalized sultite liquor and furfural in theabsence of phenolic bodies. Completion of this reaction is indicated by change in color of the liquor from In aecordance with the alternative process described above, a

'in the absence of phenolic bodies, which becomes a smooth, heavy liquid.

Since vat 4 is part of a continuous treatment apparatus, liquid is withdrawn continuously through the outlet pipe 45 controlled by opening valve 46 in carrying out the method of the type described in my previous application. Its separation from the rest of the liquid is eiected by gravity. The upper paddles of agitator 43 propel liquid upward, whereas lower paddles on it (not shown) propel liquid downward, forming two zones of circulation. As the cooking progresses the heavier reaction products settle to the lower zone from which they are drained 'through the outlet. The time of treatment is established by the rate of intiow through spout 31, the valve 46, after the vat is full, being regulated to maintain the height of the liquid in the vat constant.

The liquid removed from vat 4 may be used in that form as a binder for low specific gravity, woody iiber products, such as wall board of insulating type which is not intended to withstand appreciable mechanical stresses. Preferably, however, the'liquid is processed further by discharging it from the outlet 45 of such vat into a second vat 5 similar in character to the vat 4. This vat also is steam jacketed, or jacketed for heating by other hot fluid, supplied to the jacket through pipe 50 and discharged from such space through pipe 51. This vat likewise is provided with an agitator, including paddles 52 carried by rotary shaft 53. Y

The liquid again is heated and maintained substantially at its boiling temperature, which will still be approximately the same as that of water, and during such heating phenol is added to the liquid and stirred into it by the agitator. Such phenol must be heated to keep it iiuid if it is to be added in liquid state. A heated or steamjacketed tank 56 may serve as a reservoir for it, and thc phenol supplied from it through pipe 57 may be deposited in a trough 58 through which liquid from the discharge spout 45 of vat 4 ows into vat 5, to mix with such liquid.

The amount of phenol added is controlled by valve S9.

The reaction between the phenol and ingredients of the liquid again requires five to thirty minutes for completion, and the agitator 53 is constructed so that its upper blades force liquid upward and its lower blades force liquid downward to segregate the heavier phenol reaction products from the partially reacted portion of the vat liquid. Finally the resulting liquid, having a purple or reddish color characteristic of phenol, is drained from the vat through outlet 54, controlled by valve 55 to maintain the liquid in the vat at a constant level. It constitutes a resinous binder or ller having excellent binding qualities when set by the application of heat and which is highly water resistant. It may be used to bind woody fibers in the manufacture of high density iiberboard, called synthetic lumber or hardboard, or other ber products having a specific gravity of .9 or higher.

Where the apparatus is used to carry out the alternative process mentioned above, it is operated somewhat more on the batch principle. No tank is required and the valvc 46 will be closed, allowing a full tank 4 of alkalized sultite liquor, phenol and aldehyde to accumulate, at which time valve 11 will be closed. There will then be added to vat 4 suiiicient ketone to separate the water phase of the liquid from the synthetic resin phase, so that the former will rise to the top and the latter will sett-le to the bottom, enabling it to be drawn olf through the pipe 45. When the vat has been emptied the valve 11 will be opened and the vat 4 will be refilled. Such a batch operation of the apparatus is not particularly objectionable heausel separation of the resin and water phases does not take long` after addition of the ketone. V

The product of this alternative process is entirely comparable to the material resulting from the treatment in vat 5. as described in my Patent 2,585,977, and may be used in the way described in that patent, mixed with woody fibrous material, for making woody tiberboard, molded products, heat-setting moldable plastics,` and utilized in the manufacture of varnish or plastic paint. Moreover, for moldable plastics the liquid of this alternative process may be concentrated by centrifuging, precipitation, or both. Thus, if an acid is added, to the liquid, for example hydrochloric acid, in an amount of one to three percent by weight, a precipitate having excellent thermosetting properties, when used as a molding sub- Stance, after washing and drying, will be produced. The addition to the liquid of not more than one percent by weight of ammonium chloride alone, or accompanied by not more than one-half percent by weight of resorcinol will enable as much as eighty percentl by weight of the treated liquor to be concentrated by centrifuging into a viscous concentrate or paste.

When the derivative is to be used as a synthetic rubber product,r the mate-rial of the continuous process discharged from vat or of the alternative process from vat 4 is treated further. Such material, for example, may be boiled in a closed container which may be somewhat evacuated to encourage evaporation and recondensation. During such boiling formaldehyde and a ketone can be added, such, as acetone or methylethylketone, to produce a thick mass which may be thick enough to solidify on cooling.

if this product is then treated by the addition of Thiokol, such as the product of Thiokol Corporation designated LP2, which is a latex-like liquid organic polysulfide polymercaptan polymer, such as described in the Patrick and Ferguson Patent No. 2,466,963, a rubberlike mass as, stated on page 2 ofthe publication Thiokol Liquid Cil Polymer LP-2 of Thiokol Corporation designated LP- tially equal amounts by weight of aldehyde and phenol' are preferred. Similarly, in the second process described above where the phenol is added rst, or the phenol and ald'ehyde are mixed together and then added simultanelously, again substantially equal weights of phenol and aldehyde are preferred, the Weight of each being about fifteen percent of the weight of the concentrated and alkalized liquor going into vat 4. This process, it will be recalled, requires also the addition of a ketone, and the quantity of such ketone should be approximately one and one-half to tive percent by weight of the concentrated alkalized sulfite liquor iiowing into vat 4.

A specific example of a treatment process in accordance with that first described above which has proved to be quite satisfactory employs the following quantities and times: 1'00 pounds of raw-waste sulfite liquor'areheated`l Y and boiled at atmospheric pressure for about l5 minutes,

during which boiling 5 pounds of sodium hydroxide are added. after which the boiling is, continued for at least about 5 minutes; 5 pounds of furfural is,v added to the alkalized and concentrated liquor and the boiling is continued`4 for a still additional 5 minutes while the lliquid is agitated. If enhanced binding and water repellant qualities are desired, the boiling is continued for another 5 minutes after 5 pounds of commercial phenol has. been added. Similar times, temperatures and quantities of ingredients are suitable in carrying out the second process described, the only difference being in the sequence in which the ingredients are added. Also, in the manner described previously, addition of a ketone is required.

Utilizing the end product of the examples where phenol and furiural are included in the mixture, given immediately above in the manufacture of wallboard or other fibrous synthetic lumber product, 16 pounds of the resulting binder may be mixed with 100 pounds of woody tibrous material containing its natural moisture, and from this material a ber sheet is formed and pressed under heat and pressure according to known methods.

As representative of a typical use of the binder material obtained from vat 4 in carrying out the first proces-s described where no phenol has been added up to this point, ythe following example is presented. 1200 parts of wood fiber containing its natural moisture has mixed with it 30 parts of alum dissolved in 200 parts of water, all by Weight. With this ber mass is mixed a solution of 200 parts of .the liquid binder diluted with parts of water. The fibrous material thoroughly impregnated by `suitable mixing technique with the binder is formed into :a mat and then pressed under a pressure of 175 pounds per square inch at a temperature ranging .from 285 to 340 degrees F; The length of time such heat and pressure are applied depends upon the thickness of the mat and of :the resulting board. For a inat to produce a board 1A; inch thick, ten minutes will suice, whereas if the mat is sufficiently thick to produce a quarter inch board the time required will be 2O minutes.

In an otherwise similar wallboard manufacturing process the strength and water resistant qualities of Vthe board may be increased .substantially if lbinder drained from vvat 5' made in accordance with the rst process described,

or from Vat d made lin accordance with the second process described where a ketone has been added, is utilized in the same proportions stated above instead of the intermediate product obtained from vat 4. The tensile strength of [the board resulting from the use of these l processes may be increased if parts of sodium silicate A further example of a fiberboard making process by which a board smoothon bothA sides may be produced, for example of Vlg-inch thickness, is cited: parts of dry wood fiber material are mixed with 16 to 33 parts of .the binder liquid obtained from vat 5 by weight where the first process has been utilized, that is, where the aldehyde reaction is completed first and the phenol is added thereafter, or obtained from vat 4 in -the manner described in accordance with the second or alternative process where the phenol and aldehyde are added to gether and a ketone is used. A mart of this mixture can adattano Vsetting phenol-formaldehyde resin of a type conventional- `ly`used in the manufacture of plywood. Preferably approximately equal parts of-sulfite liquor resin and such -phenol-formaldehyde resin are mixed together.

To this mixtureff binders is'added from two to three percent of flake sodium hydroxide by weight of the sulte liquor derivative, for the lpurpose of rendering it compatible 4with the phenol-'formaldehyde resin. Alternatively, from three to ve percent of the sulfte liquor binder component `by weight'of paraformaldehyde may be used. rl`his plywood glue may be spread in the conventional manner -by the usual veneer glue spreader, and the plywood 'formed in a hot press operating at a temperature of 300 F. and 175 pounds per square inch pressure for a period of five minutes, for exarnple.- If desired, a somewhat vlower temperature, for example 275 F., may be employed, `in which event it may be necessary to heat the product for a somewhat longer period. The temperature, pressure and timeA for-setting the glue is not par- ]ticularly critical and is in accordance with conventional plywood manufacturing technique.

It has been found that the combination of sulfite liquor 'derivative and thermo'setting phenol-formaldehyde resin of a type conventionally used in the manufacture of plywood is much more stable .than phenol-formaldehyde :resin alone, so that in the mixed forni it can be used after standing for a number of hours, sometimes as much as twenty-four hours, whereas phenol-formaldehyde resin l to be suiciently effective must be applied and subjected to heat sufficient to effect its setting within a fraction of Y' an hour, usually approximately one-half hour, in order lto have sufficient strength.

Where it is desired to have a colored fiberboard prodluctsuch color may be incorporated in the fiber mixture by combining pigment with the resin. It has been found,

however, that the colors vproduced by mixing metallic pigment f with thermoset-ting phenol-formaldehyde resin alone of a type conventionally used in the manufacture of plywood are inclined to fade readily. When the pigment is mixed with a minor proportion of sulte liquor derival tive, however, whether of the type produced by the first or second process described, the pigment is rendered compatible with the phenol-formaldehyde resin. It is desirable to use `a major proportion of thermosetting phenolvformaldehyde resin and a minor proportion of suliite liquor derivative, because the former is relatively light in color whereas the (latter is dark in color, and if too f much were used it would tend to mask the effect of the pigment.

As specific examples, approximately one-half as much metallic oxide pigment as of sulfite liquor derivative by weight is employed Iand the mixture of pigment and suliite liquor derivative is then mixed with from five to ten times the amount of thermosetting phenol-iormalde` l oxide.

, or zso. -For stronger colors more pigment is used, such" hyde resin by weight. A typical pigment is chromium In order to insure thorough blending the combination of pigment and sullite liquor resin should be stirred with such phenol-fonnaldehyde resin for an hour as'a weight equal 'to or even somewhat greater than the weight of sulfite liquor derivative.

In ,using the binder thus colored in the manufacture of A. fiberboard the same proportion of such colored binder as previously proposed for unpigmented binder may be mixed with the woody fiber material. Various commercially available colors,'including red, green, blue, or appropriete color mixtures, have proven to bequite stable in berboard against bleaching or darkening when mixed with sulfte liquor derivative, whereas almost invariably the color of such board has faded or darkenedwhere the pigment was utilized with phenol-formaldehyde resin alone.

"In the production of an elastomer material, to the product of the first process removed from vat 5 or the product of the second or alternative process removed from vat 4 a small amount of sodium hydroxide may beadded, such as approximately one percent (dry weight) of the weight of sulfite liquor derivative, although this caustic Valkali preferably is in aqueous solution containing forty percent solid NaOH. At the same time is added approximately three percent by weight of the sulfite liquor resin of formaldehyde, and this mixture is boiled until complete blending has occurred. If the mixture is too thick water may 'be added, and, in addition, `approximately five percent by weight of the sulfite liquor resin of a ketone is added, such as acetone, methylethyl ketone, methyl-isopropyl ketone, methyl-butyl ketone, methyl-iso-butyl ketone or methyl-benzyl ketone. The mixture is thickened fby this addition, and it should be brought to the boiling point to insure complete reaction. On cooling, the resin will solidify. The `addition of a small quantity, such as from .01 to .02 of a percent by weight of the sulfite liquor resin, of lead naphthenate or cobalt naphthenate will reu- 4der the solid ofthe general consistency of rubber, forming 'of it an elastomer which can be vulcanized as previously explained. A more direct method of obtaining an elastomer from lwaste sulte liquor concentrated to approximately fifty percent` solids in the presence ofv approximately one percent 0f flake sodium hydroxide by weight of the rawy or loriginal sulfite liquor is as follows. During ebullition five percent approximately of the concentrated sulfite'liquor Iby weight of sodium hydroxide is added, and after ebullition has ceased approximately five percent by weight of the waste'suliite liquor of furf-ural is added, and heating is continued until ebullition ceases. While the 'batch i is still hot five percent by weight of the condensed sulfitc liquor of phenol is added, and the entire mixture is then boiled for two hours in a closed container, as explained previously. Approximately three percent by Weight of the `condensed sulfite liquor of formaldehyde is then added, and the liquid is boiled in the closed container for another hour. The addition of approximately three percent lby weight of the concentrated suliite liquor of a latex-like liquid organic polysulde polymercaptan polymer, as previously discussed, may then be added to convert the material to an elastomer as previously explained.

While some variation in the proportions of the various ingredients will not alter the resulting derivative appreciably, the examples given are typical.

I claim as my invention:

l. The method of treating waste sulte liquor which comprises adding to the liquor caustic alkali, adding phenol and furfural to the alkalized liquor, the phenol `being added at least as soon as the Vfurfural is added, heating the resulting liquid and thereafter adding a ketone to such resulting liquid.

- is methylethylketone.

4. The method dened in claim l, including adding Lformaldehyde to the resulting product, boiling such. re-

sulting product and the formaldehyde in a closed container, and `adding a ketone.

5. The method defined in claim 4, in which the later Q ketone added is acetone.

6. The method defined in claim 4, in which the later ketone added is methylethylketone.

7. The method Vdefined in claim 4, in which a latex-like liquid organic polysulfide polymercaptan polymer is added to the resulting product in an amount by weight equal to a few percent of the weight of the sulite liquor content.

8. The method of treating waste sulite liquor which comprises adding to the liquor caustic alkali, adding phenol and furfural to the alkalized liquor, heating the resulting liquid, adding formaldehyde and boiling the liquid in a closed container, and adding a ketone to such resulting liquid.

9. The method defined in claim 8, and thereafter adding a latex-like liquid organic polysuliide polymercaptan polymer in an amount by weight equa'l to a few percent of the weight of the sulte liquor content.

10. A thermal setting resin binder incorporating the reaction product of phenol, furfural and a ketone with alkalized concentrated sulte liquor.

11. A vulcanizable elastomer comprising a latex-like liquid organic polysulde polymercaptan polymer and formaldehyde with the product of phenol and furfural reacted with alkalized concentrated sulite liquor, the amount of such latex-like liquid organic polysulde polymercaptan polymer being by weight equal to a few percent of the weight of the sulfite liquor content.

12. A vulcanizable elastomer comprising a latex-like liquid organic polysulde polymercaptan polymer and formaldehyde with the product of phenol, furfural and a ketone reacted with alkalized concentrated sulte liquor, the amount of such latex-like liquid organic polysulde polymercaptan polymer being by weight equal to a few percent of the weight of the sulte liquor content.

13. The method of making a fiber product comprising mixing a metallic pigment with a thermosetting resin binder incorporating the reaction product of furfural with alkalized concentrated sulte liquor, mixing such colored resin binder with thermosetting phenol-formaldehyde resin, mixing such combined resin with woody ber, and molding the resin impregnated fiber mass under heat and pressure.

14. The method of making a fiber product comprising mixing a metallic Lpigment with a thermosetting resin binder incorporating the reaction prod uct of furfural with alkalized concentrated sulte liquor, mixing a minor proportion by weight of such colored resin binder with a major proportion by weight of thermosetting phenolformaldehyde resin, mixing such combined resin with 10 woody fiber, and molding the resin impregnated liber mass under heat and pressure.

15. The method of making a ber product comprising mixing a minor proportion by weight of a metallic pigment with a major proportion by weight of Ia thermosetting resin binder incorporating the reaction product of furfural with alkalized concentrated sulte liquor, mixing a minor proportion by weight of such colored resin binder with a major proportion by weight of thermosetting phenol-formaldehyde resin, mixing such combined resin with woody ber, and molding the resin impregnated fiber mass under heat and pressure.

16. The method of making a fiber product comprising mixing a metallic pigment with `a thermosetting resin binder incorporating the reaction product of furfural and phenol with alkalized concentrated sulfite liquor, mixing a minor proportion by weight of such colored resin binder with a major proportion by weight of thermosetting phenol-formaldehyde resin, mixing such combined resin with woody ber, and molding the resin impregnated ber mass under heat and pressure.

17. A colored thermosetting resin binder comprising a minor proportion by weight of a pigmented thermosetting resin binder embodying the reaction product of furfural with alkalized concentrated sulite liquor and a major proportion by weight of thermosetting phenol-formaldehyde resin.

18. The binder defined in claim 17, in which phenol is included in the pigmented thermosetting sullte liquor resin.

19. A colored thermosetting resin binder comprising a pigmented furfural and sulte liquor reaction product blended with a thermosetting phenol-formaldehyde resin.

20. A fiber product comprising a consolidated mass including discrete pieces of woody material impregnated with a pigmented furfural and sultte liquor reaction product blended with a thermosetting phenol-formaldehyde resin.

References Cited in the le of this patent UNITED STATES PATENTS 1,143,714 Knight June 22, 1915 2,585,977 Uschmann Feb. 19, 1952 FOREIGN PATENTS 476,344 Great Britain Dec. 7, 1937 

1. THE METHOD OF TREATING WASTE SULFITE LIQUOR WHICH COMPRISES ADDING TO THE LIQUOR CAUSTIC ALKALI, ADDING PHENOL AND FURFURAL TO THE ALKALIZED LIQUOR, THE PHENOL BEING ADDED AT LEAST AS SOON AS THE FURFURAL IS ADDED, HEATING THE RESULTING LIQUID AND THEREAFTER ADDING A KETONE TO SUCH RESULTING LIQUID. 